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The present study was initiated to examine the measures of dietary intake of Fe, Cu and Zn. The food duplicate samples were collected in Busan and its neighboring area, from the 69 middle-aged women (healthy non-smoking, mostly house wives), who provided informed consent. The samples were wet ashed by being heated in the presence of mineral acids, and Fe, Cu, Zn in the wet-ashed samples were analyzed by inductively coupled plasma - atomic emission spectrometry(ICP-AES). Dietary intake of Fe, Cu and Zn were 10.4 mg/day in Fe, 1.2 mg/day in Cu, 7.4 mg/day as arithmetic mean. The values for dietary Fe and Zn were lower, and the values for dietary Cu were higher than the recommended daily intake from Korean Nutrition Society. Further studies of Korean foods are needed to clarify the representative values for daily dietary Fe, Cu and Zn intake in the Korean population.

This study was performed to evaluate the congeners of polychlorinated dibenzo-p-dioxins(PCDDS) and polychlorinated dibenzofurans(PCDFs) in Korean foods among children in Korea, in comparison with the findings in their mothers. The PCDDs and PCDFs intakes of 24-h diet duplicates were estimated from the previous Korean reports. In Korean children and their mothers of this study, major sources of lipid intake were plant-based foods(62% for children, 66% for their mothers). The women took 34% of lipid from animal sources, among which meats were leading sources of animal lipids(30%). Fish and shellfish were accounted for 4% in total lipid intake. Daily intake of PCDDs and PCDFs in the children md their mothers were 0.002-3.188 and 0.002-2.717 pg WHO-TEQ/day in animal sources and ND-0.283 and ND-0.296 pg WHO-TEQ/day in plant sources, respectively. PCDDs/PCDFs intake from animal origin was the major exposure source for both children and their mothers in Korea. Among the 17 PCDD/Fs congeners, 2,3,4,7,8-pentachlorodibenzofuran was assumed to be the effective exposure marker for diet intake.

The dependence of annealing temperature on stress and microstructure in damascene Cu was examined by X-ray diffraction and transmission electron microscopy. The measured hydrostatic stress was found to increase with increasing annealing temperature in the case of narrow lines. Microstructure analysis using TEM revealed that the grain sizes increased with increasing annealing temperature. Also, the line width dependence of stress in Cu/low- k was compared with that of Cu/SiO 2 . Although the measured hydrostatic stress of Cu/low- k is somewhat lower than that of Cu/SiO 2 , the differences in stress between narrow line and wide lines is much larger. Through finite element analysis, the stress gradient between via and line is higher for the case of Cu/low- k . In addition, it was found that the stress gradient is more important than stress itself when low- k is used as dielectric materials because void formation cannot effectively relax the strain energy of the system. This stress gradient between via and line, which is the driving force of vacancy diffusion, is larger when the low- k with lower stiffness and higher thermal expansion is used for dielectric layer. For this reason, it is suggested that the Cu/low- k can be more vulnerable to stress-induced voiding.

The anisotropic spread of the central peak in a (111) pole figure by x-ray diffraction (XRD) was observed for damascene Cu lines of 0.18–2 µm in width and 0.5 µm in depth. The spread originates from the existence of slightly tilted (111) grains because of inclined sidewalls. The tilted (111) orientation is favorable only for polygranular clusters whose sidewall energies can be minimized simultaneously. Consequently, bamboo grains have an exact 〈111〉 orientation, while the polygranular clusters have a tilted 〈111〉 orientation. Using this concept, the volume fraction of the bamboo grains and polygranular clusters in the damascene Cu lines were quantified using the XRD pole plots.

The present study was initiated to examine the dietary intake, blood level and urinary concentration of lead (Pb) and cadmium (Cd) among children in Korea, in comparison with the findings in their mothers.Peripheral blood, spot urine and 24-h food duplicate samples were collected in Busan, Korea, from 38 pairs of children (4-10 years of age) and their mothers (28-46 years, non-smoking, mostly housewives), who provided informed consent. Samples were wet-ashed by being heated in the presence of mineral acids, and Pb and Cd in the wet-ashed samples were analyzed by graphite furnace atomic absorption spectrometry. Pb and Cd in food (Pb-F, Cd-F), blood (Pb-B, Cd-B) and urine [observed value (Pb-Uob, Cd-Uob), and values corrected for creatinine (Pb-Ucr, Cd-Ucr) or a specific gravity (1.016; Pb-Usg, Cd-Usg)] were presented in terms of geometric mean (GM) and geometric standard deviation (GSD).Pb-F and Cd-F in the children were 0.337 microg Pb and 0.457 microg Cd/kg body weight per day as GM, respectively. Pb-B and Cd-B were 38.0 microg Pb and 1.51 microg Cd/l, and Pb-U and Cd-Uob were 5.44 microg Pb/l and 1.33 microg Cd/l, respectively. Pb-F and Pb-B for children were not significantly different from the values for their mothers. In contrast, Cd-F and Cd-B were significantly different between children and their mothers. Cd-F for children correlated with Cd-F for mothers, but no significant correlation was observed in Cd-B, Cd-U, Pb-F, Pb-B or Pb-U between children and their mothers. The dietary intake of Pb in total Pb intake (i.e., respiratory and dietary intake) accounted for 51.7 and 64.8% in children and their mothers, respectively, whereas the corresponding proportions were 97.8 and 98.2%, respectively, for Cd.Cd intake was exclusively from food, both in children and mothers. Dietary Cd intake of children significantly correlated with that of their mothers. Dietary Pb intake in children, however, did not correlate with that of their mothers. Pb uptake from ambient air tended to be higher in children than in their mothers.

The dihedral angle distribution of electroplated (EP) Cu films is significantly broader than those of vapor-deposited films, which may indicate anisotropy of the grain boundary energies. Additives incorporated during EP are presumed to cause anisotropy in the grain boundary energy and abnormal grain growth during self-annealing.

Microtexture of 0.18μm, 0.25μm, 0.70μm, and 2μm widths Cu damascene line is measured by EBSD technique. The image drift could be reduced by the shortening of measurement time, and could be completely removed by selected area mapping technique. Using carbon and gold dual layer coating method, image drift and pattern indexing fraction is improved but the EBSD pattern quality is decreased. By increasing the accelerating voltage from 15kV to 20kV, pattern quality loss could be compensated without resolution loss. Strong {111} texture is obtained in 0.18 and 0.25μm line, and weak {111} texture is observed in 2μm line. And every line was observed to have more than 60% CSL boundaries.

The line width dependence of stress in damascene Cu was examined experimentally as well as with a numerical simulation. The measured hydrostatic stress was found to increase with increasing line width. The larger stress in an interconnect with large dimension is attributed to the larger grain size, which induce higher growth stress in addition to thermomechanical stress. A stress model based on microstructure was constructed and the contribution of the growth and thermal stress of the damascene lines were quantified using finite element analysis. It was found that the stress of the via is lower than that of wide lines when both the growth stress and thermal stress were considered. This stress gradient between via and line, which is the driving force of vacancy diffusion, is larger when the low-k with lower stiffness and higher thermal expansion is used for dielectric layer. For this reason, the Cu/low-k can be more vulnerable to stress-induced voiding.

The adoption of Cu and various low‐k materials as metal lines and dielectrics has aggravated new stress‐related problems such as huge voiding near a via and via‐cracking. It is thought that these failures are originated from the inherent characteristics of damascene Cu lines and thermo‐mechanical properties of low‐k dielectrics. In this study, we analyzed the microstructure and stress of damascene Cu with various line width and dielectric materials. The relationship between microstructure, stress and mechanical properties of dielectric materials was described though the finite element analysis based on experimental data. Finally, the effect of microstructure and dielectric materials on stress‐related failure mechanism was discussed.

Various low-k materials are being pursued as dielectric materials for future interconnects. However, poor thermo-mechanical properties of low-k materials cause tremendous reliability concerns, thus the proper materials for integration with Cu are not suggested yet. In this study, the line width and spacing dependence of damascene Cu lines embedded by TEOS and low-k materials (CORAL) was analyzed using x-ray diffraction. Generally, the hydrostatic stress of Cu/TEOS was greater than that of Cu/CORAL, while the opposite for von-Mises stress. Using a three-dimensional finite analysis (FEA), the effect of low-k materials on the stress and its distribution in via-line structures of dual damascene Cu interconnects was studied. In the case of Cu/TEOS, the hydrostatic stress was concentrated at the via and on the top of the lines, where it was suspected that the void would nucleate. On the other hand, in the via-line structures integrated with organic low-k materials, large von-Mises stress was maintained in the via. Therefore, the deformation of via, rather than voiding, may be the main failure mode in the interconnects with low-k materials.

Following the trend of miniaturization of VLSI devices, the current density of flip-chip ball bumps has increased significantly and each solder joint is supporting a current density close to 10/sup 4/ A/cm/sup 2/. Therefore, in SnPb eutectic solder, which has a high diffusivity at the operating temperature due to its low melting point, electromigration became a major reliability threat. We have investigated electromigration behavior of eutectic SnPb solder using thin stripe-type specimens. From the 80/spl deg/C and 100/spl deg/C testing, the activation energy for electromigration was calculated as 0.9 eV and the dominant diffusion paths were through interface and surface. From the compositional analysis, it was found that Pb is a dominant migrating species over Sn atoms for 100/spl deg/C testing.

Damascene Cu interconnects show significant differences in both their microstructural and stress behavior as compared to those of Al interconnects patterned using the etching process. Thermal stresses build up during the successive thermal cycles due to the differences in the coefficients of thermal expansion of the component materials. Other than these thermal stresses, growth stresses originating from grain growth develop in damascene Cu interconnects as well. In this study, the linewidth dependence of the stress in damascene Cu was examined experimentally, as well as by numerical simulation. The stresses of damascene Cu with widths ranging from 0.13to2μm were measured using x-ray diffraction, and the measured hydrostatic stress was found to increase with increasing linewidth, in contrast to the typical behavior of Al interconnects. Microstructure analysis using transmission electron microscopy revealed that the grain sizes increased with increasing line dimensions. The increase in stress in the interco...